There has been conventionally known a technology of locally forming a sound field using a speaker.
As such a technology, for example, there is proposed a local sound field formation technology that is based on superdirective control using a parametric speaker (e.g. refer to Non-Patent Literature 1).
In addition, for example, there is also proposed a technology of forming a sound field in which a sound can be heard only in the neighborhood of a speaker array, by generating evanescent waves using the speaker array (e.g. refer to Patent Literature 1).
Meanwhile, in public places such as an airport and a station, operating information and a signage are presented using a video display. By using a voice in addition to a video, while it becomes possible to present content more effectively, the voice is delivered also to a large indefinite number of people not requiring the information.
In view of the foregoing, it becomes convenient to enable different sounds to be reproduced in a remote location and a neighboring location by presenting only the minimum guide to people in the remote location, and presenting detailed information to people in the neighboring location, for example. For example, at a cash dispenser in a bank, there is a voice intended to be heard only by a person performing a manipulation in the neighborhood of the cash dispenser, and a voice intended to be heard by people in a remote location, such as “you forgot something”.